The present invention relates to an industrial robot adjustment device capable of adjusting the position of a tip end of an industrial robot easily to the origin assumed by software of the industrial robot.
In conventional robot systems, absolute X and Y axes assumed by the software used for driving the robot are set in fixed directions with respect to the robot body. To ensure effective MDI (Manual Data Input) operations, the robot should be mounted to a processing machine such as a lathe or other processing machine with which the robot is employed, in such a manner that the X and Y axes of the machine and the X and Y axes assumed by the software are accurately aligned. (See, for example, Published Examined Japanese Patent Application No. 21362/1980). (The MDI operations involve entering the values for the directions of the X and Y axes with respect to the robot, and the X and Y dimensions, and moving the robot to the required positions).
However, it is generally the case that the direction of the X and Y axes of the software are not indicated on the body of the robot. Moreover, the bolt-holes provided for attaching the robot to the attachment base of the lathe or the like allow a certain degree of slack, and hence it is not always the case that the X and Y axes of the software and the X and Y axes of the processing machine are correctly aligned with each other. When there occurs such misalignment of the X and Y axes of the software and the X and Y axes of the processing machine, the movements of the robot may interfere with the processing machine, and thus there is the danger of damage to either or both of these assemblies.
In order to solve the above described difficulties accompanying the conventional device, an industrial robot adjustment device has been proposed, in which the tip-end portion of arms of an industrial robot is positioned at the end portion of a jig that has been positioned and installed at a fixed position relative to the X and Y axes of the processing machine in advance, and the position of the tip-end portion thereof is taken as the point of origin for the MDI operations.
FIGS. 1 to 3 show an example of such an industrial robot adjustment device capable of adjusting the tip-end portion of the robot to the origin of the software programmed for the robot device. In the figures, (1) designates a robot base fixedly mounted on an installation base (2) of a processing machine. (3) designates a robot body provided to the robot base (1) in such a manner that the body 3 is allowed to rotate in the direction indicated by an arrow .theta..sub.1. (4) is a first arm which is mounted on the robot body (3) in such a manner that the first arm (4) is allowed to swing in a direction .theta..sub.2, (5) is a second arm which is mounted at the upper end of the first arm (4) in such a manner that the second arm (5) is allowed to swing in a direction .theta..sub.3, (6) is a third arm which is mounted on the tip end of the second arm (5) in such a manner that the third arm (5) is allowed to rotate in a direction .theta..sub.4, (7) is a tip-end member which is mounted on the third arm (5) in such a manner that the tip-end member (7) is allowed to swing in a direction .theta..sub.5 and (8) is a flange which is detachably mounted at the lower end of the tip-end member (7) in such a manner that the flange (8) is allowed to rotate in a direction .theta..sub.6. Accordingly, the industrial robot shown in FIG. 1 is a six-axes type industrial robot having six-degrees of freedom. (10) designates a jig which is fixed on the installation base (2) with an end portion of the jig (10) in close contact with a reference surface of the robot base (1). Further, the jig (10) is positioned at a predetermined position relative to the processing machine. Dimensions A and B thereof are determined to specific values in advance and so the upper end surface of the jig (10) is located at a predetermined set position. (11) denotes three pins of the same shape and dimensions, which are planted on the tip-end surface of the flange (8) and are arranged at equal intervals on the periphery of a circle centering on a rotation axis (9) of the flange (8). (12) denotes three pins that are planted on the upper end surface of the jig (10) in correspondence with the pins 11.
With such an industrial robot adjustment device as shown in FIG. 1, the robot is actuated so that the pins (11) on the flange (8) are accurately positioned to the respective pins (12) on the jig (10) and then the position of the robot is determined as the point of origin for MDI adjustment. In this case, however, in order to check the contact between the pins (11) and the pins (12), it is necessary for an operator who is responsible for achieving measurements to enter the robot's work envelope, which is dangerous. In addition the precision of checking of the state of contact is relatively poor since the checking is done visually. It is also disadvantageous in that since adjustment is effected through the contact of the pins (11) and (12) that have the same shape and dimensions, there is risk of misadjustment to a position that is displaced by a 120.degree. or 240.degree. turn relative to the rotation axis (9).